Lingual Orthodontic Treatment Research Articles

Favourable dentoalveolar changes after lower premolar extractions for Class III camouflage with completely customized lingual appliances

BackgroundThe aim of the investigation was to evaluate if the inclination of the lower anterior teeth can be controlled reliably after lower premolar extraction for Class III camouflage treatment with completely customized lingual appliances (CCLAs). Treatment outcome was tested against the null hypothesis that lower premolar extractions for non-surgical camouflage treatment of a Class III malocclusion will lead to further compensation by retroclining mandibular incisors during CCLA treatment.MethodsThis retrospective study included 25 patients (f/m 12/13; mean age 20.7 years, SD 9.5 years) with uni- or bilateral Class III molar relationship and a Wits value of ≤ -2 mm. In all consecutively debonded patients, lower premolars were extracted to correct the sagittal relationship with a non-surgical camouflage approach. Lateral head films prior to (T1) and at the end of lingual orthodontic treatment (T2) were used to evaluate skeletal and dentoalveolar effects. A paired t-test with alpha = 5% was used to define differences between the endpoints. The linear correlation between the inclination of the mandibular incisors at T1 and the achieved correction was measured with the Pearson correlation coefficient (PCC). A Schuirmann’s TOST equivalence test was used to check if the final lower incisor inclination was within the defined norms.ResultsThe null hypothesis was rejected as the mean lower incisor inclination was improved by 1.8° despite lower premolar extractions (T1: 86.8°/ T2: 88.6°). There was a strong correlation (-0.75) between the lower incisor inclination at T1 and the achieved correction indicating a controlled correction towards the norm regardless of the initial incisor position. At T2, the interincisal angle as well as the lower incisor inclination were within the norm.ConclusionLower premolar extractions for non-surgical camouflage treatment of a Class III malocclusion will not lead to undesired retroclining of mandibular incisors during CCLA treatment even in severe cases.

Modified single rigid vacuum-formed indirect bonding trays for lingual bracket application: a case report

Abstract Lingual orthodontic treatment offers an aesthetic alternative but presents unique challenges in bracket positioning. The present article introduces a modified design and fabrication process for rigid vacuum-formed indirect bonding trays for lingual bracket application. The technique is presented through a clinical case report of an adult patient who presented with bimaxillary dentoalveolar protrusion and managed using lingual appliances, premolar extractions, and mini-screws. The modified rigid vacuum-formed trays enabled the accurate simultaneous bonding of multiple teeth as well as individual teeth. The technique offers several advantages over existing indirect bonding methods, including time-saving, simplicity, easy removal of excessive adhesive, and potential cost-effectiveness. The superimposition of post-bonding scans and the digital orthodontic setup showed high agreement between the planned and actual bracket positions. Additionally, the close alignment between the planned orthodontic setup and the achieved treatment outcome highlights the reliability of the technique for predictable lingual orthodontic treatment. Further clinical studies with larger sample sizes are needed to confirm the effectiveness of this technique.

Lingual bracket transfer accuracy of double vacuum-formed indirect bonding tray using 3D-printed model: an in vivo study

This study aimed to assess the transfer accuracy of a digital indirect bonding method for lingual brackets using double vacuum-formed trays invivo. Twenty-five patients in need of lingual orthodontic treatment were consecutively recruited. Bracket placement was performed on ideal setups, followed by fabricating indirect bonding trays through vacuum-forming on 3-dimensional printed models. Transfer accuracy was measured at each bracket after superimpositions of postbonding scans and reference data. One-tailed t tests were used to determine whether bracket deviations were within the limit of 0.5 mm and 2° for linear and angular dimensions, respectively. A total of 611 lingual brackets were evaluated. Mean linear transfer errors were 0.06 mm, 0.09 mm, and 0.12 mm, with frequencies of deviations within the 0.5 mm limit of 99.7%, 99.8%, and 98.0% for mesiodistal, buccolingual, and occlusogingival dimensions, respectively. Regarding angular measurements, mean transfer errors were 1.28°, 1.73°, and 2.96°, with frequencies of deviations within the 2° limit of 81.0%, 68.9%, and 51.1% for rotation, tip, and torque, respectively. Mean errors fell within the clinically accepted limits for all linear dimensions and rotation but exceeded the limit for tip and torque. Lingual bracket indirect bonding using double vacuum-formed trays fabricated on 3-dimensional printed models has high transfer accuracy in the mesiodistal, buccolingual, and occlusogingival dimensions and rotation. However, the transfer of tip and torque is less accurate.

Lever arm on bracket vs. lever arm on archwire: A 3D finite element method study of mechanics of miniscrew-supported lingual en-masse retraction of maxillary anterior teeth

To compare the deformation of the main archwire and 3D movements of maxillary anterior teeth during miniscrew-supported en-masse retraction with the lever arm on the archwire and on the brackets in lingual orthodontic treatment in finite element analysis (FEM) simulation. A 3D dental-alveolar model with bonded 0.018×0.025-inch slot lingual brackets and a 0.017×0.025-inch dimension stainless-steel archwire was created. Four FEM models were created based on a 3D dental-alveolar model: in Models A and C, the lever arms were attached to the lingual bracket, while in Models B and D, the lever arms were attached to the archwire. Meanwhile, in Models A and B, the miniscrews were placed in between the molars, while in Models C and D, the miniscrews were positioned on the palatal roof. After a 1.5N retraction force was applied from the miniscrew to the end of the lever arm, the initial movements in the sagittal, transversal, and vertical planes were recorded and analysed for maxillary anterior teeth. In Models B and D, smaller deformation of the main archwire and less prominent bowing effect were noticed in both sagittal and vertical directions compared to their counter groups. In Models C and D, the central incisors showed less torque loss in the sagittal direction and more canine intrusion vertically. For the same lever arm-miniscrew retraction configuration, the lever arm on the bracket showed less deformation of the main archwire and more body movement of the teeth than the lever arm on the archwire group. With the same level arm height, the transverse and vertical bowing effect is reduced when the lever arm was placed distal to the central incisor and the miniscrews placed next to the palatal suture.

In-office Customized Brackets: Aligning with the Future.

Digital technology introduced many innovations in the field of dentistry and orthodontics in the last years. The most important advancement was the ability to digitize the oral cavity using intraoral scanners. CAD software have been around for decades, but only in the last twenty years started showing up in the field of dentistry and orthodontics. 3D printers are not new in the field of manufacturing. Nevertheless, their inclusion in the orthodontist armamentarium was made possible only the last few years, while new printing materials have been also invented, allowing the manufacturing of many appliances previously made using traditional laboratory procedures. Orthodontic treatment is mainly based on the use of fixed appliances. The vast majority of orthodontists use commercial straight-wire brackets while customized brackets are preferred mostly for lingual orthodontic treatment. New CAD software called Ubrackets allows the in-office designing and printing of customized brackets using hybrid ceramic crown resin or zirconia slurry. Some scientific studies have been conducted to investigate the bracket printing outcome in terms of mechanical properties. More studies must be performed to allow the inclusion of in-office designing and printing of customized brackets in the orthodontic armamentarium.

Conventional and self-ligating lingual orthodontic treatment outcomes in Class I nonextraction patients: A comparative study with the American Board of Orthodontics Objective Grading System

This study aimed to assess and compare the duration and outcomes of orthodontic treatment with conventional and self-ligating lingual fixed appliances with the American Board of Orthodontics (ABO) Objective Grading System. Thirty consecutive patients with a complete dentition and Angle Class I malocclusion treated with a conventional lingual bracket system (STb; Ormco, Glendora, Calif) or self-ligating lingual bracket system (GC Experience-L; GC Orthodontics, Breckerfeld, Germany) were included. The occlusal outcome was assessed with the ABO instrument. The treatment duration and ABO scores of the 2 groups were recorded. Statistical analyses were evaluated using independent-sample t tests. The conventional group had a mean treatment time of 2.10 ± 0.69 years, and the self-ligating group had a treatment duration of 1.68 ± 0.48 years (P>0.05). The mean posttreatment ABO scores in the conventional group were 20.23 ± 5.13, and the mean posttreatment ABO scores in the self-ligating group were 21.00 ± 5.66. No difference was found between the groups regarding the criteria of ABO (P>0.05). The highest scores were given in the assessment of buccolingual inclinations in both conventional and self-ligating lingual bracket groups. The design of the lingual appliances used in this study did not influence the treatment duration and the total ABO scores in treating patients with a Class I relationship in this sample. Both types of lingual brackets were especially deficient in correcting buccolingual inclinations. The strengths were their ability to close spaces and correct anterior rotations and overjet regardless of the bracket types.

Digital lingual appliance combined with micro-screws for the treatment of a skeletal bimaxillary protrusion and ‘gummy’ smile

Abstract This case report describes the lingual orthodontic treatment of a 28-year-old female patient who presented with a bimaxillary protrusion malocclusion, a hyperdivergent facial pattern, mentalis strain, and a ‘gummy’ smile. To achieve favourable occlusal and facial results, the four first premolars were extracted, and micro-screws utilised to provide maximum anchorage. With the widespread application of three-dimensional technology, a digital goal-oriented treatment plan was applied for its predictability and precision. A fully customised lingual appliance system with preset torque in the anterior teeth combined with ribbon-wise arch wires was placed to prevent excessive lingual inclination of the incisors during retraction. As a result, an attractive facial profile and a well-aligned dentition with ideal intercuspation was obtained.

Periodontal Parameters in Fixed Labial and Lingual Orthodontic Treatment: A Systematic Review and Meta-Analysis.

To critically evaluate the periodontal parameters of patients receiving fixed labial and lingual orthodontic therapy. The current systematic review was registered at PROSPERO. Clinical studies comparing the periodontal parameters between fixed labial and lingual orthodontic treatment were searched up to June 2022 in four electronic databases, and unpublished literature was searched at ClinicalTrial.gov. The risk of bias of randomised controlled clinical trials (RCTs) and non-randomised clinical trials (n-RCTs) was assessed using the Cochrane risk-of-bias tool 2.0 and the Risk of Bias in Non-randomised Studies of Interventions (ROBINS-I) assessment tool, respectively. The pooled periodontal parameters were calculated in random-effect meta-analyses. The confidence of evidence was assessed via the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Eight studies involving 223 patients were included in the current study. The risk of bias was high for 2 RCTs and 3 n-RCTs, and moderate for 3 n-RCTs. Patients receiving fixed lingual orthodontic treatment showed a lower plaque index (MD = -0.14; 95%CI -0.27 to -0.02). No statistically significant difference was found in the bleeding on probing index (MD = 0.11; 95%CI -0.03 to 0.25), gingival index (MD = 0.02; 95%CI -0.06 to 0.11), and periodontal pocket depth ( MD = 0.06; 95%CI -0.16 to 0.27) between the two groups. The overall quality of the evidence was very low to low. The present study indicates no obvious difference in periodontal parameters between the fixed labial and lingual orthodontic systems, although the overall quality was very low to low. Further RCTs with standardised outcome measures are needed.

Evaluation of angulation between labial & lingual surfaces of crown of anterior teeth & 3D mapping lingual surface for development of concept of new preadjusted lingual bracket

Introduction: Lingual orthodontics grew slowly in North America in the 1980s as orthodontists grappled with the lingual technique, which needed distinct treatment planning and a different approach to biomechanics, as well as ergonomics and treatment efficacy difficulties. The early excitement of lingual orthodontic treatment faded with the discovery of "tooth-colored" labial brackets manufactured from single-crystal sapphire and later from ceramics, and much of the improvement of lingual orthodontics occurred outside the United States. Removable orthodontic aligners, rather than lingual braces, have become the treatment option for patients seeking invisible orthodontics with the introduction. The present work focuses of digital analysis and evaluation of angulation between labial & lingual surface of crown of each anterior tooth and lingual curvature for the development of pre adjusted lingual bracket system. Material & Methods: Sample consists of 100 dental cast (maxillary & mandible) and 100 CBCT scans made at Santosh Dental College, Ghaziabad which were selected on the basis of Angle’s Class I molar relationship without any crowding, rotation, attrition, abrasion, erosion, abfraction & anomaly on any tooth with the patient age group between 16 years to 20 years. CBCT scans were taken by KODAK 9500 Cone Beam 3D System (Carestream Health, Inc. 

Three-dimensional comparison of the effects of sliding mechanics in labial and lingual orthodontics using the finite element method

The extraction of maxillary first premolars is usually the treatment of choice to resolve crowding, alveolar protrusion, or Class II malocclusion. The demand for a lingual orthodontic treatment is increasing because of its esthetic value; therefore, understanding lingual biomechanics is essential to every clinician. This study compared the 3-dimensional (3D) effects of sliding mechanics in labial and lingual orthodontics using the finite element method. Twelve 3D finite element models were created with different power arm heights and miniscrew positions. A 150 g of retraction force was applied from the head of the miniscrew to the power arm. The 3D displacement of the original nodes was measured, and the stress distribution on defined element zones of the periodontal ligament. Different force directions led to different movement patterns and stress distribution. The lingual models showed a more important lingual crown tipping, extrusion, and higher stress values than the labial models. Results were not affected by the vertical position of the miniscrew. Bodily en-masse retraction was not achieved in all models. Adding extra torque to the archwires is essential to prevent excessive lingual crown tipping. The lingual appliance induced more lingual tipping and extrusion of the anterior teeth. Expanding the archwire is important to minimize the risk of intercanine width reduction. The vertical position of the miniscrew does not affect the results of en-masse retraction.

Effects of Skeletally Supported Anterior en Masse Retraction with Varied Lever Arm Lengths and Locations in Lingual Orthodontic Treatment: A 3D Finite Element Study.

Objective This study is aimed at analyzing different points of force application during miniscrew supported en masse retraction of the anterior maxillary teeth to identify the best line of action of force in lingual orthodontic treatment. Materials and Methods Three-dimensional (3D) finite element models were created to stimulate en masse retraction with different heights and positions of the miniscrew and lever arm to change the force application points; a 150 g retraction force was applied from the miniscrew to the lever arms, and the initial tooth displacements were analyzed. Results Lingual crown tipping and occlusal crown extrusion were seen at all heights and positions of the miniscrew and lever arm, but when the miniscrew height was at 8 mm and the power arm was located between the lateral incisors and canines, these tipping patterns were less than those obtained with a 4.5 mm high miniscrew and a lever arm located distal to the canines. Conclusion All miniscrew heights and lever arm positions showed initial lingual crown tipping and labial root tipping with occlusal crown extrusion. However, the 8 mm miniscrew height and the lever arm located between the lateral incisor and canine showed fewer amounts of these tipping patterns than a 4.5 mm miniscrew height and lever arm located distal to the canines. Therefore, this could be the preferred point of force application during en masse retraction in lingual treatment with additional torque control methods.

A comparison of treatment results of adult deep-bite cases treated with lingual and labial fixed appliances.

To compare the cephalometric treatment results of adult deep-bite cases after labial and lingual fixed orthodontic treatment. A total of 102 patients underwent lingual orthodontic treatment and complete records were evaluated. The following inclusion criteria were used: patients who had Angle Class I or mild Class II malocclusion; comprehensive orthodontic treatment that did not include intrusion mechanics or any extractions; patients with an initial overbite of more than 3.7 mm. Thirteen patients met the inclusion criteria. These cases were matched with the same number of patients according to age with a labial orthodontic treatment group. Pre- and post-treatment cephalometric radiographs were evaluated. Independent t test or Fisher exact tests were performed to assess the differences between the groups. Proclination of the upper incisors was higher in the labial group. Incisor mandibular plane angle (IMPA) showed an increase of 1.2° in the lingual group and 9.7° in the labial group. Lower incisor edge was approximately in a stable sagittal position in the lingual group but significant lower incisor proclination was seen in the labial group. The lower incisors were intruded (-1 mm) in the lingual group but lower incisors were minimally extruded (0.3 mm) in the labial group. No significant difference was found in the movements of upper and lower molars for both groups. The nature of lower incisor movement involved less protrusion in lingual orthodontics than the labial treatment. Lingual orthodontic treatment is a better option in adult cases where intrusion of lower incisors without labial tipping is desired.

Effectiveness of Fully Customized Lingual Orthodontic Treatment: A Retrospective Pilot Study

Objective: To investigate the effectiveness of Suresmile ® lingual therapy on torque, tip, and rotations measures through digital evaluation of planning and post-treatment digital models . Material and Methods: A sample of 12 Caucasian adult patients (4 men; mean age 30.6 years ± 3.9 and 8 women; mean age 31.4 years ± 4.5) treated with the Suresmile ® lingual orthodontic technique was retrospectively selected, regardless of the type of malocclusion. Digital planning was performed with Suresmile ® software, while lingual therapy was accomplished with interactive self-ligating lingual brackets and customized Suresmile ® arches. First, digital models of planning and post-treatment digital models were compared using VAM software (and the discrepancies were analyzed through MANOVA and four multivariate. Then, Tukey and Bonferroni's post-hoc tests are performed. Results: The accuracy average values are 60.11 ± 27.67% for torque, 53.52 ± 27.37% for tip and 59.19 ± 26.42% for rotation, while for inaccuracy values are 2.72° ± 2.23° for torque, 2.98° ± 2.16° for tip and 3.58° ± 3.29° for rotation. No significant differences have been recorded evaluating different sectors of both arches . Conclusion: This retrospective preliminary study highlight how overcorrections, especially in the Suresmile lingual technique, should be performed during orthodontic planning. Moreover, the study gets bases for further, more structured future studies that should involve larger and more homogeneous samples.

Oral Discomfort And Impaired Oral Function In The Fixed Lingual Orthodontic Treatment

Introduction: Aesthetic consideration has become an important component for patients to decide the use of fixed orthodontic appliance, one of which is the fixed lingual orthodontic appliance. However, there are still many complaints about the discomfort felt by the patient that affects their compliance to the treatment. This paper aims to deliver the knowledge regarding oral discomfort and impaired oral function in the fixed lingual orthodontic treatment to be used as operator and patient education material. Materials and Methods: “lingual braces” was the sole keyword used in three journal databases (Google Scholar, ScienceDirect, and PubMed) resulted in 11 journals that was used in this paper. Results: complaints were mostly about speech disturbance (6 journals), discomfort on the tongue (5 journals), pain (1 journal), difficulty in cleaning the oral cavity (4 journals), difficulty in chewing and dietary changes (3 journals), and caries (2 journals). Discussion: discomfort arising during treatment was largely associated with the reduced space which was occupied by the tongue at rest. This resulted in the continuous contraction of the tongue muscles. The contraction increases discomfort and resulted in impaired oral functions such as speech and chewing. The use of bracket that is closer to the surface of the teeth can reduce complaints. Conclusion: the lingual orthodontic bracket position and type of the system used in the treatment affects the patient's comfort. Most of the discomfort appeared in the first 3 months of treatment and decreased with time.

Incorrect measurements and misleading conclusions in the article \u201cComparison of the efficacy of tooth alignment among lingual and labial brackets: an in vitro study\u201d

Background/objectiveTo reproduce the methods and results of the study by Alobeid et al. (2018) in which the efficacy of tooth alignment using conventional labial and lingual orthodontic bracket systems was assessed.Materials/methodsWe used the identical experimental protocol and tested (i) regular twin bracket (GAC-Twin [Dentsply]) and lingual twin bracket systems (Incognito [3M]), (ii) together with NiTi 0.014” wires (RMO), and (iii) a simulated malocclusion with a displaced maxillary central incisor in the x-axis (2 mm gingivally) and in the z-axis (2 mm labially).ResultsThe method described by Alobeid et al. (2018) is not reproducible, and cannot be used to assess the efficacy of tooth alignment in labial or lingual orthodontic treatment. Major flaws concern the anteroposterior return of the Thermaloy-NiTi wire ligated with stainless steel ligatures. The reproduced experimental setting showed that a deflected Thermaloy-NiTi wire DOES NOT move back at all to its initial stage (= 0 per cent correction) because of friction and binding (see supplemented video), neither with the tested labial nor with the lingual brackets. Furthermore, an overcorrection of up to 138 per cent, which the authors indicate for some labial bracket-wire combinations and which deserves the characterization “irreal”, stresses the inappropriateness of the method of measurement.Further flaws include: a) incorrect interpretation of the measurement results, where a tooth tripping around (overcorrection) is interpreted as a better outcome than a perfect 100 per cent correction; b) using a statistical test in an inappropriate and misleading way; c) uncritical copying of text passages from older publications to describe the method, which do not correspond to this experimental protocol and lead to calculation errors; d) wrong citations; e)differences in table and bar graph values of the same variable; f) using a lingual mushroom shaped 0.013” Thermaloy-NiTi wire which does not exist; g) drawing uncritical conclusions of so called "clinical relevance" from a very limited in vitro testing.ConclusionsClinical recommendations based on in vitro measurements using the Orthodontic Measurement and Simulation System (OMSS) should be read with caution.

Comparison of the Periodontal Status of Patients Undergoing Labial and Lingual Orthodontic Therapy.

AimTo compare the periodontal status in relation to the lower anteriors of patients between labial and lingual orthodontic therapy.Materials and methodsThe study includes a total of 20 patients in the age group of 20-30 years. All the included patients were selected with limited lower anterior crowding within 0-8 mm. The subjects were randomly divided into two groups: labial (n=10) and lingual (n=10) fixed orthodontic therapy. The periodontal status was evaluated using three indices, plaque index, calculus index, and gingival index, at two different treatment intervals - the first month and the third month - of orthodontic treatment. ResultsThe values of all the three indices at both time intervals were tabulated. There was no statistical significance when compared to the values in the first month. In the third month, all three indices were statistically significant for both labial and lingual therapy (p<0.001). The lingual appliance had more plaque and calculus accumulation.ConclusionTherefore, the study proves that the lingual surface of patients undergoing lingual orthodontic treatment exhibits more plaque and calculus deposition, thereby the weakening of the periodontal status.

Lingual Orthodontic Treatment: Efficacy and Complications

Aims and Objectives: The high esthetic demands led to the promotion of various esthetic appliances like lingual orthodontics. This study aimed to review clinical outcome and potential complications of lingual orthodontics to achieve an evidence-based decision for orthodontic therapies. Materials and Methods: A comprehensive electronic search was conducted from January 1975 to March 2019 which was limited to English language and administrations of lingual orthodontics treatment which evaluated its efficacy and potential complications. Data extraction was performed according to the PRISMA statement. Results: 49 studies were selected and analyzed in this systematic review. The pain of lingual appliances starts a little earlier and lasts longer, and patients with lingual appliances experience more tongue discomfort and less cheek and lip pain and greater eating difficulties especially after placement and take a longer time to adapt to appliances. Lingual appliances generally cause more plaque accumulation and gingivitis especially in lingual anterior teeth; however, labial appliances are associated with high frequency in posterior maxillary teeth. Conclusion: This systematic review shows that despite the drawbacks of these appliances such as pain and eating difficulties, they can accomplish treatment goals with the same outcomes in comparison with conventional approaches, within the same duration and even lesser anchorage loss.

Comparison of potential long-term costs for preventive dentistry treatment of post-orthodontic labial versus lingual enamel cavitations and esthetically relevant white-spot lesions: a simulation study with different scenarios

BackgroundPost-orthodontic white-spot lesions (WSL) in esthetically relevant incisor and canine areas impair dentofacial esthetics, and preventive dentistry treatment is definitely required in case of enamel cavitations. The incidence of lingual post-orthodontic WSL and cavitation following lingual MB treatment has been reported to be distinctively decreased compared to labial MB treatment. Moreover, lingual WSL do not impair dentofacial esthetics. It was the objective of this study to calculate consequential costs of preventive dental care necessary to recover labial or lingual post-orthodontic cavitations as well as esthetically relevant WSL following either labial or lingual MB interventions.MethodsMB treatments (labial / lingual) were simulated in 1,000,000 patients between the ages of 12-18Y, with a median residual life time expectancy of 58Y based on local mortality tables. Range of MB Tx duration was 9–45 mo. Frequencies of post-orthodontic (labial / lingual) enamel damages were derived from large-scale WSL incidence studies. Anterior composite survival rates were based on a systematic review on the subject. Within the context of the German dental fee system (GOZ 2.3 and 3.5 fee increments), simulation of costs for enamel damage treatment and re-treatment (maximum: 5x) were based on single-surface composite restorations for lingual or labial cavitations and labial WSL treatment; and lingual WSL fluoridation.ResultsOverall mean total costs for Tx and re-Tx of both WSLs and cavitations may sum up to 1718.91 Eur in the high-cost (GOZ 3.5) scenario for conventional MB cases, versus 19.94 Eur for lingually treated cases, given that renewal of simulated single-surface restorations takes place at 15-year intervals. When focussing on patients diagnosed with least of one WSL, and/or cavitation, these mean costs increase up to 2332.35 Eur for conventionally treated MB patients, or 65.03 Eur for lingual MB patients.ConclusionCosts for repeated treatment of post-orthodontic enamel damages produced by conventional vestibular fixed appliances may easily exceed the initially higher costs associated with lingual orthodontic treatment. Judged economically in the long term, lingual MB Tx may be considered as a more cost-effective solution for a correction of malocclusion.

Finite element analysis of the effect of power arm locations on tooth movement in extraction space closure with miniscrew anchorage in customized lingual orthodontic treatment.

More patients are choosing customized orthodontic appliances because of their excellent esthetics. It is essential that clinicians understand the biomechanics of the tooth movement tendency in customized lingual orthodontics. This study aimed to evaluate the tooth movement tendency during space closure in maxillary anterior teeth with the use of miniscrew anchorage in customized lingual orthodontics with various power arm locations. Three-dimensional finite element models of the maxilla were created with miniscrews and power arms; the positions were varied to change the force directions. A retraction force (1.5N) was applied from the top of the miniscrews to the selected points on the power arm, and the initial displacements of the reference nodes of the maxillary teeth were analyzed. After applying force in different directions, power arms located at the distal side of the canines led to larger initial lingual crown tipping and occlusal crown extrusion of the maxillary incisors compared with power arms located at the midpoint between the lateral incisors and canines, and caused a decreasing trend of the intercanine width. In customized lingual orthodontic treatment, power arms located at the distal side of the canines are unfavorable for anterior teeth torque control and intercanine width control. Power arms located at the midpoint between the lateral incisors and canines can get better torque control, but still cannot achieve excepted torque without extra torque control methods, no matter whether its force application point is higher than, lower than, or equal to the level of the top of the miniscrews.

Quantitative analysis of biofilm formation on labial and lingual bracket surfaces.

To evaluate and compare the biofilm formation between labial and lingual orthodontic brackets. Twenty patients with a mean age of 24 ± 8.8 who had received labial or lingual orthodontic treatment were enrolled in the study. Biofilm formation on 80 brackets was analyzed quantitatively with the Rutherford backscattering detection method. Five micrographs were obtained per bracket with views from the vestibule/lingual, mesial, distal, gingival, and occlusal aspects. Quantitative analysis was carried out with surface analysis software (ImageJ 1.48). Data were analyzed by Mann-Whitney U and Kruskal-Wallis tests (α = 0.05). Total biofilm formation was 41.56% (min 29.43% to max 48.76%) on lingual brackets and 26.52% (min 21.61% to max 32.71%) on labial brackets. Differences between the two groups were found to be significant. No difference was observed in intraoral location. The biofilm accumulation was mostly located on gingival, mesial, and distal surfaces for both groups. The biofilm accumulation on lingual orthodontic therapy was found to be more than labial orthodontic therapy.